Juno was so much grieved when she saw Argus stretched dead in the grass on the hilltop, that she took his hundred eyes and set them in the tail of a peacock; and there you may still see them to this day.

Then she found a great gadfly, as big as a bat, and sent it to buzz in the white cow’s ears, and to bite her and sting her so that she could have no rest all day long.  Poor Io ran from place to place to get out of its way; but it buzzed and buzzed, and stung and stung, till she was wild with fright and pain, and wished that she were dead.  Day after day she ran, now through the thick woods, now in the long grass that grew on the treeless plains, and now by the shore of the sea.

[Illustration:  “She cried out to him and told him to let the cow go.”]

By and by she came to a narrow neck of the sea, and, since the land on the other side looked as though she might find rest there, she leaped into the waves and swam across; and that place has been called Bosphorus—­a word which means the Sea of the Cow—­from that time till now, and you will find it so marked on the maps which you use at school.  Then she went on through a strange land on the other side, but, let her do what she would, she could not get rid of the gadfly.

After a time she came to a place where there were high mountains with snow-capped peaks which seemed to touch the sky.  There she stopped to rest a while; and she looked up at the calm, cold cliffs above her and wished that she might die where all was so grand and still.  But as she looked she saw a giant form stretched upon the rocks midway between earth and sky, and she knew at once that it was Prometheus, the young Titan, whom Jupiter had chained there because he had given fire to men.

“My sufferings are not so great as his,” she thought; and her eyes were filled with tears.

Then Prometheus looked down and spoke to her, and his voice was very mild and kind.

“I know who you are,” he said; and then he told her not to lose hope, but to go south and then west, and she would by and by find a place in which to rest.

She would have thanked him if she could; but when she tried to speak she could only say, “Moo! moo!”

Then Prometheus went on and told her that the time would come when she should be given her own form again, and that she should live to be the mother of a race of heroes.  “As for me,” said he, “I bide the time in patience, for I know that one of those heroes will break my chains and set me free.  Farewell!”

Then Io, with a brave heart, left the great Titan and journeyed, as he had told her, first south and then west.  The gadfly was worse now than before, but she did not fear it half so much, for her heart was full of hope.  For a whole year she wandered, and at last she came to the land of Egypt in Africa.  She felt so tired now that she could go no farther, and so she lay down near the bank of the great River Nile to rest.